Reverse link power control in an orthogonal system

• US 20060002346A1
• Filed: 12/22/2004
• Published: 01/05/2006
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Arak Sutivong, Avneesh Agrawal
• Original Assignee: Arak Sutivong, Avneesh Agrawal
• Inventors: Agrawal, Avneesh, Sutivong, Arak
• Granted Patent: US 7,594,151 B2
• Time in Patent Office: Days
• US Class Current: 370/332
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/286 during data packet transmission, e.g. high speed packet access [HSPA]
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment

Abstract

A closed-loop reverse-link power control algorithm for a frequency hopping orthogonal frequency division multiple access (FH-OFDMA) system is described. The power control algorithm adjusts the user'"'"'s transmit power based on effective carrier-to-interference (C/I) and Received-Power-Over-Thermal (RpOT) measurements. The algorithm is inherently stable and is effective for FH-OFDMA systems with retransmissions.

Claims

1. A method of reverse link power control, comprising:

transmitting a packet;

determining whether the packet has been received without error;

decreasing an effective carrier-to-interference (C/I) setpoint if the packet has been received without error; and

increasing the effective C/I setpoint if the packet has not been received without error.

2. The method of claim 1, wherein

determining whether the packet has been received without error involves determining that there is no packet error and that the packet is not missing.

3. The method of claim 2 further comprising:

transmitting a negative acknowledgment (NACK) messages for data packets not received.

4. The method of claim 3 further comprising:

retransmitting said data packets not received in accordance with said NACK messages.

5. The method of claim 3, wherein said data packets are transmitted over one or more time slots.

6. The method of claim 1, further comprising determining whether a Received Power Over Thermal (RpOT) is greater than a maximum Received Power Over Thermal (RpOT_max).

7. The method of claim 6, wherein the Received Power Over Thermal (RpOT) is the ratio between the received signal power and thermal noise.

8. The method of claim 6, further comprising issuing a down command if the RpOT is not greater than the RpOT_max.

9. The method of claim 6, further comprising determining whether an effective carrier-to-interference ratio (C/I) is less than an effective carrier-to-interference ratio for the setpoint (C/I_sp).

10. The method of claim 9, further comprising determining whether a Received Power Over Thermal (RpOT) is less than a minimum Received Power Over Thermal (RpOT_min).

11. The method of claim 10, further comprising issuing a down command if the effective carrier-to-interference ratio (C/I) is not less than the effective carrier-to-interference ratio for the setpoint (C/I_sp) or the Received Power Over Thermal (RpOT) is not less than the minimum Received Power Over Thermal (RpOT_min).

12. The method of claim 10, further comprising issuing an up command if the effective carrier-to-interference ratio (C/I) is less than the effective carrier-to-interference ratio for the setpoint (C/I_sp) and the Received Power Over Thermal (RpOT) is less than the minimum Received Power Over Thermal (RpOT_min).

13. The method of claim 1, wherein the steps of

determining whether the packet has been received without error;

decreasing an effective carrier-to-interference (C/I) setpoint if the packet has been received without error; and

increasing the effective C/I setpoint if the packet has not been received without error comprise an outer loop power control.

14. The method of claim 13, wherein the outer loop power control is disabled if the Received Power Over Thermal (RpOT) is less than or equal to the minimum Received Power Over Thermal (RpOT_min).

15. The method of claim 13, wherein the outer loop power control is disabled if the Received Power Over Thermal (RpOT) is greater than or equal to the maximum Received Power Over Thermal RpOT_max.

16. The method of claim 13, wherein the outer loop power control is enabled if the Received Power Over Thermal (RpOT) is greater than the minimum Received Power Over Thermal (RpOT_min) and the Received Power Over Thermal (RpOT) is less than the maximum Received Power Over Thermal RpOT_max.

17. A wireless communications device, comprising:

means for transmitting a packet;

means for determining whether the packet has been received without error;

means for decreasing an effective carrier-to-interference (C/I) setpoint if the packet has been received without error; and

means for increasing the effective C/I setpoint if the packet has not been received without error.

18. The wireless communications device of claim 17, further comprising means for determining whether a Received Power Over Thermal (RpOT) is greater than a maximum Received Power Over Thermal (RpOT_max).

19. The wireless communications device claim 18, further comprising issuing a down command if the RpOT is not greater than the RpOT_max.

20. A processor programmed to execute a method of estimating interference in a wireless communication system, the method comprising:

transmitting a packet;

determining whether the packet has been received without error;

decreasing an effective carrier-to-interference (C/I) setpoint if the packet has been received without error; and

increasing the effective C/I setpoint if the packet has not been received without error.

21. The processor of claim 20, wherein the method further comprises determining whether a Received Power Over Thermal (RpOT) is greater than a maximum Received Power Over Thermal (RpOT_max).

22. The processor of claim 21, wherein the method further comprises issuing a down command if the RpOT is not greater than the RpOT_max.

23. A computer readable media embodying a method of reverse link power control, the method comprising:

transmitting a packet;

determining whether the packet has been received without error;

decreasing an effective carrier-to-interference (C/I) setpoint if the packet has been received without error; and

increasing the effective C/I setpoint if the packet has not been received without error.

24. The computer readable media of claim 23, embodying a method of reverse link power control, the method further comprising determining whether a Received Power Over Thermal (RpOT) is greater than a maximum Received Power Over Thermal (RpOT_max).

25. The computer readable media of claim 24, embodying a method of reverse link power control, the method further comprising issuing a down command if the RpOT is not greater than the RpOT_max.